284 RECENT DEPOSITS OF NERBUDDA VALLEY. 



The shells, however, which oecur in this deposit, distinctly and in 

 the most unquestionable manner prove its fresh-water origin ; that is 

 as far down as Hosungabad ; and there is no reason to suppose that 

 any portion of the bed was deposited under different conditions : not that 

 the intrusion of brackish or salt water into the valley towards its mouth 

 is itself an improbability, but from the absence of all proofs counte- 

 nancing such a supposition. Near Hatnora, Birman Ghat, and other 

 spots, this red clay contains great numbers of fluviatile shells of species 

 now living in the district, among which the Uniones are conspicuous 

 from their size and numbers. Where these shells are most abundant, 

 the clay often assumes a dark tint, probably from the amount of decayed 

 animal matter contained in it. The shells are invariably perfect as when 

 alive, the bivalves being united, the hinge ligament entire, and the inside 

 frequently empty or merely partially occupied with a little dark clay, 

 chiefly the residue of the animal ; or merely lined with a coating of 

 calcareous spar. 



The following shells* have been noticed in the lower group, and also 



g] ,, . , , occur throughout the upper one as well, being 



S rou P- equally abundant in either, though usually locally 



congregated, often in prodigious numbers, both in the clay, and arena- 

 ceous beds. 



Gasteropoda. 

 Melaniadse. 

 Melania tuberculata Mull. Not rare 



Rather small, and with the apex entire. 



Paludinidae. 

 Paludina Bengalensis Lam. Very common. 



This shell often occurs of a large size, and an impoverished variety 

 is not rare. 



* The shells here enumerated have been identified by aid of a collection authentically 

 named by Mr .Benson, whose extensive acquaintance with Indian shells is well known. 



